docs: def extend_children(self, parent, wanted_children, child_class, child_glossary=None):
          """
          Extend the number of children so that the parent object contains wanted children.
          No child will be removed if wanted_children is smaller than the current number of children.
          """
          from cms.api import add_plugin
          current_children = parent.get_num_children()
          for _ in range(current_children, wanted_children):
              child = add_plugin(parent.placeholder, child_class, parent.language, target=parent)
              if isinstance(child_glossary, dict):
                  child.glossary.update(child_glossary)
              child.save()